Code
Paste this snippet wherever you want the wave to show up:

<div id="wave" style="width: 560px; height: 420px"></div>

And this one right before your

</body> tag:

<script
  type="text/javascript"
  src="http://wave-api.appspot.com/public/embed.js">
</script>
<script type="text/javascript">
  var wave =
    new WavePanel('https://wave.google.com/wave/');
  wave.setUIConfig('white', 'black', 'Arial', '13px');
  wave.loadWave('googlewave.com!w+HdSKjKzWN');
  wave.init(document.getElementById('wave'));
</script>